RELEVANCE: This study will test a novel percutaneous osseointegrated prosthetic implant for transfemoral amputees as an alternative to a socket prosthetic limb attachment system. This work aims to address the complications associated with socket technology with a device that is implanted directly into the residual bone and can be used to improve the quality of life for Veterans amputees. Dr. Erik Kubiak and his collaborators have the clinical and research foundation on which to successfully complete this work. The Department of Veterans Affairs currently provides care for over 340,000 individuals with limb loss. The rate of amputations within the U.S. military population has doubled over the past decade as a result of the Operation Enduring Freedom and Operation Iraqi Freedom conflicts compared to previous wars. The majority of these amputees are eager to regain function but face ongoing burdens as a result of their limb loss. The current prosthetic socket system is fraught with complications and is difficul to use in cases where the residual limb is short and with multiple-limb loss. Commonly, socket wearers experience recurring complications, which include skin breakdown due to friction, discomfort, limb pain, infection, insecure socket fixation, and frequent re-fitting due to body mass changes. These challenges prohibit most amputees from comfortably wearing their prosthesis more than a few hours a day. OBJECTIVE: The objective of this study is to test a novel percutaneous osseointegrated prosthetic implant in Veteran transfemoral amputees. The following specific aims will be tested: AIMS: 1) Evaluate a new percutaneous prosthetic attachment system for safety in a limited number of human subjects (N=10); 2) Optimize the surgical technique for implanting the percutaneous osseointegrated prosthetic attachment system in a limited number of human subjects; 3) Develop post-operative monitoring and rehabilitation techniques specific for subjects implanted with this percutaneous osseointegrated device to measure efficacy; 4) Build the clinical platform for transferring osseointegrated technology to other VA and military institutions. METHODS: Ten subjects that have undergone transfemoral amputation not due to peripheral vascular disease, complications from diabetes, or infection will be enrolled at the George E. Wahlen VA Medical Center, Salt Lake City, Utah. All subjects will receive the percutaneous osseointegrated device. The surgical protocol will consist of a two-stage procedure. The endo-prosthetic portion of the device will be implanted at Stage 1. The exo-prosthetic portion of the device will be implanted six weeks later to allow the soft tissue envelope to mature and regain a viable blood supply. Subjects will be systematically monitored for one year following the Stage 2 surgery for data collection. Subjects will be followed for life as part of routine clinical care. Each subject will undergo careful assessment prior to the implant surgery and during the one-year follow-up period. Radiographs, DEXA scanning, microbiology and validated tools for monitoring activity, impairment and patient satisfaction will be used to objectively quantify prosthetic utilization and patient quality of lif. SIGNIFICANCE: The success of this novel percutaneous osseointegrated prosthetic device has the potential to significantly improve VA clinical care for amputees by reducing complications associated with traditional socket attachment system. This research would also greatly improve the Veteran's function and overall quality of life.